The present invention relates to a switching device, for example a residual-current-operated protective device or a combination switch, for disconnecting and switching at least one line of a power supply, and more particularly a switching device with an optional line-voltage-dependent switching functionality, without requiring a dedicated line-voltage-dependent trigger element.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
Switching equipment of this type is used in electrical engineering applications, in particular in building installations or in the home. When an undesirable condition occurs, for example a residual current, overcurrent or overvoltage, these switching devices should respond and disconnect the affected circuit from the voltage supply.
Residual-current-operated protective devices (RCDs) or combination switches (RCBOs) are classified according to their technical function as line-voltage-independent (“VI” or voltage-independent) or as line-voltage-dependent (“VD” or voltage-dependent). In accordance with conventional product standards (e.g., EN/IEC 61008, 61009, 61947, . . . ), full functionality is provided in the first case also during line voltage failure (VI); however, in the latter case only when the line voltage supply is present (VD).
The published international application WO 2006/007608 A2 discloses a FI (fault-interrupter) circuit breaker which provides voltage-independent basic functionality, but can also accommodate an optional additional module (control module) which provides additional voltage-dependent functionality. For this purpose, two trigger elements are included in the FI circuit breaker, with one of these trigger elements operating in voltage-independent mode (permanent magnetic trigger) and the other operating in voltage-dependent mode (operating current trigger) on a common latch. When the additional module is inserted and the line voltage is applied, the voltage-independent trigger is bypassed and only the voltage-dependent trigger is activated.
This switching device disadvantageously has a complex construction, because many components have to be provided twice for the voltage-independent and the voltage-dependent trigger. Because each of the two types of the triggers requires a respective dedicated trigger element, this applies particularly to those configurations where a later installation of an additional module is not contemplated.
It would therefore be desirable and advantageous to provide an improved switching device for switching a line of a power supply, which obviates prior art shortcomings and is able to specifically allow continued operation with and without an additional module having voltage-dependent functionality. Moreover, no components should have to be provided that are not already required for the pure voltage-independent operation. In addition, conventional voltage-independent switching devices should be easily adaptable, and the functional reliability should be increased in voltage-dependent operation.